Tirek and/or Grogar in season 3.

I, personally, think it would definitely serve as a love letter to the older generations of MLP if Tirek and/or Grogar would appear in season 3 as villains. And I am sure I'm not the only fan who thinks this.
But the questions remain: what would their evil plans be? How would they be redesigned? Who would voice them?
Well, for the last question, here are my personal choices of candidates: Mark Hammil, Tim Curry, Chris Adler, John DiMaggio.
This thread is basically for discussion for the possibility of Tirek and/or Grogar being in the upcoming season, focusing mostly around the aforementioned questions and others.
So what do you all think?